Currently plastic body panels cannot be processed through conventional powder coating systems that are in place at automotive assembly plants without the result of a surface defect as shown in prior art FIG. 1 for a conventional class “A” SMC panel that has a smooth surface finish and a linear shrinkage of ±0.06%. The primer surface is the coating layer underlying color coat and clean coat. Primer surface coating applications are currently shifting towards powder systems to facilitate electrostatic primer coat application to a component. The plastic components currently represent poor powder coating substrates owing to moisture content that can exceed 0.9% component weight percent. This is unfortunate since plastic body panel components afford several attractive attributes over steel such as cost, resistance to corrosion and dents, and fuel savings. In order to render plastic components amenable to powder priming, powder deposition has conventionally been performed at elevated temperature, and inevitably decreasing coating efficient and promoting component sag.
Thus, there exists a need for a sheet molding compound having a low moisture content that facilitates room temperature vapor barrier coating as a precursor to powder primary.